How to fix Microsoft Defender SmartScreen was not able to scan python-manager-26.3.msix. You shouldn't keep it unless you're sure it's safe on my windows PC

That warning means Windows marked the .msix file as coming from the internet and SmartScreen could not complete its reputation or safety check. The safest way to proceed is to verify the file before opening it.

1. In File Explorer, locate python-manager-26.3.msix.
2. Right-click the file and select Properties.
3. On the General tab, check for the message that the file came from another computer and might be blocked.
4. If that message appears, only select Unblock if the file came from a trusted source.
5. Before opening it, scan the file with Microsoft Defender Antivirus.

To improve Defender detection before scanning:

1. Go to Start > Settings > Update & Security > Windows Security > Virus & threat protection.
2. Select Manage settings.
3. Make sure Cloud-delivered protection and Automatic sample submission are turned On.
4. Go back to Virus & threat protection.
5. Under Virus & threat protection updates, select Check for updates.
6. Under Threat definitions, select Check for updates.

If Defender still does not detect or fully assess the file, run Microsoft Safety Scanner:

1. Download and open Microsoft Safety Scanner.
2. Choose a scan type and start the scan.
3. Review the results on screen.
4. For detailed results, check %SYSTEMROOT%\debug\msert.log.

If Windows continues warning on this file specifically, that can also happen because downloaded files carry security metadata from the internet. In that case, only open or unblock the file after confirming the source is trusted and the antivirus scan is clean. Turning off Microsoft Defender SmartScreen is possible in Edge under Settings > Privacy, search, and services > Security, but doing so makes the device more vulnerable and is not the recommended fix.

Also check whether multiple antivirus products are installed. Running more than one antivirus or antispyware program at the same time can reduce performance, cause instability, or trigger unexpected restarts. If an old or unwanted security app is installed, remove it from Start > Settings > Apps.

If the file still cannot be scanned and there are broader security issues on the PC, run the Windows Security troubleshooter to automatically check and enable security features such as SmartScreen, UAC, DEP, Windows Firewall, and antivirus status.

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